A basic guide to canonical links and what it means for SEO

A canonical link is a special html/code placed on a webpage, created to show search engines that another page should be considered the preferred version or original source of that specific content.

What Google has to say about canonical links:

“If you have a single page accessible by multiple URLs, or different pages with similar content (for example, a page with both a mobile and a desktop version), Google sees these as duplicate versions of the same page. Google will choose one URL as the canonical version and crawl that, and all other URLs will be considered duplicate URLs and crawled less often. 

If you don’t explicitly tell Google which URL is canonical, Google will make the choice for you, or might consider them both of equal weight…”

What is a canonical link?

In short, a canonical link is used to tell search engines that similar URLs have the same content.

It often happens that the same content can be found on different websites, and by using a canonical link, you can tell search engines which website to prefer in search engine results without harming your search engine rankings.

For example, when bloggers are sent press releases, it is often uploaded to multiple websites without any changes made to the actual copy. When this happens, several websites will have similar URLs with the exact same content (the copy is a 100% match). This could lead to search engines tagging your content as duplicate content and you can run the risk of being penalised by search engines (your webpages could be crawled less often, or not at all).

Another example is when an online store sells their products in different countries around the world and therefore uses multiple websites. It would mean that similar products could appear across all of their websites (depending on how you landed on that specific product page). To avoid having duplicate content issues, these websites will need to use canonical links to point search engines to the preferred source of content.

Here’s a look at an example of two similar URLs that contains the same content:

https://mywebsite.com/product/seo-tools /

https://mywebsite.com/product/seo/tools/

To decide which version search engines show in search results, we use a canonical link.

In this case, it is best practice to use a canonical link to point to the original or preferred version of the content and to avoid duplicate content issues. When used correctly, canonical links can improve your website’s SEO.

ALSO READ: What is the difference between follow and no-follow links?

What does a canonical link look like?

The HTML element (or code) that is used to tell search engines about the original source of content on a website is: rel=canonical.

A canonical link would usually look like this:

Original content: https://mywebsite.com/product/seo-tools /

Similar URL with the same content: https://mywebsite.com/product/seo/tools/

<link rel=“canonical” href=“https://mywebsite.com/product/seo-tools /” />

When to use a canonical link

There are several reasons when a canonical link is necessary. Here are the two most important reasons for canonical links:

1. Same content, similar URLs. There are several websites that republish content from other websites, or stores with multiple websites that sell the same products, etc. When this happens, it is best SEO practice to use a canonical link to direct search engines to the preferred, original source of the content.
2. Your home page. Unfortunately, there are several ways in which someone can link to your home page. It can be https://www.yourhomepage.com or http://www.yourhomepage.com or perhaps even https://yourhomepage.com. To the human eye, it looks like the same URL, but to search engines, it looks like different pages with the same content. Although Google recently announced that it is not crucial to have self-referencing canonicals, it is best practice to show search engines which URLs you want to rank.

If you are unsure of which URL to pick for canonicalization, just pick one. The results will be far better than not having any canonical links.

How to use a canonical link

When you have two versions of the same page with similar URLs (because the same content can be found in different sections of your website), you will need to use a canonical link to show search engines which page you would prefer to rank in search engine results.

To do this, you have to choose which one of your two pages will be the canonical version. This should be the page you think is the most important.

It doesn’t matter which page you choose to be the preferred version of your page. It could be the page with the most visitors, or the page with the most links to. The other page will then contain your canonical link.

Then, add a rel=canonical link on the non-preferred page to show search engines that you want your preferred page to rank in search engine results.

In other words, if we take the example above, and chose https://mywebsite.com/product/seo-tools / as the main, preferred URL, then we will have to put a canonical link on the other URL (https://mywebsite.com/product/seo/tools/ ) to show search engines that we want the first URL to rank.

We will put the following code <link rel=“canonical” href=“https://mywebsite.com/product/seo-tools /” /> in the <head>  section of the page.

Setting up canonical links is really as easy as adding a simple html in the <head> section of a page. Doing this creates a “soft redirect” between the pages, without actually redirecting the user, and it shows search engines which webpage you prefer to be ranked in search engine results. Both URLs are now seen as one URL by search engines.